Safety apparatus for landing gates on hoist elevators

ABSTRACT

A hoist control system having electrical control circuits for each landing gate, and contact breakers in the control circuits in sealed containers mounted on the hoist adjacent each landing gate, the contact breakers being magnetically operable from the exterior of the container, and mechanical landing gate latching means, incorporating magnets which close the contacts when the landing gates are closed and mechanically latched.

United States Patent Inventor Murray Hutner 562 Briar Hill Ave., Toronto, Ontario, Canada Appl. No. 831,335

Filed June 9, 1969 Patented Dec. 7, 1971 SAFETY APPARATUS FOR LANDING GATES 0N HOIST ELEVATORS 12 Claims, 7 Drawing Figs.

Int. Cl 1366b 1/00 Field of Search 187/48-50,

References Cited UNITED STATES PATENTS 1,446,668 2/1923 Shepherd 187/61 3,054,475 9/1962 Moser 187/48 3,056,470 10/1962 Moser 187/61 3,198,902 8/1965 Deshautreaux.. 335/207 3,205,323 9/1965 Deshautreaux 335/207 Primary Examiner-Harvey C. Hornsby Attorney-George A. Rolston ABSTRACT: A hoist control system having electrical control circuits for each landing gate, and contact breakers in the control circuits in sealed containers mounted on the hoist adjacent each landing gate, the contact breakers being magnetically operable from the exterior of the container, and mechanical landing gate latching means, incorporating magnets which close the contacts when the landing gates are closed and mechanically latched.

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SHEET 3 [IF 3 R E m wmw U w WW/ I e W 4/.P M 6 ATENT AGENT SAFETY APPARATUS FOR LANDING GATES ON IIOIST ELEVATORS This invention relates to a safety device for use with landing gates on construction hoists for elevators and more particularly to an electrical control device which provides electrical continuity in an electrical circuit when all the gates on the elevator are safely closed permitting the elevator to be operated.

Elevators presently in use must have a safety device attached to the landing gate at each landing where the elevator is to be stopped to permit people to enter or exit from the elevator. A safety device is required by law to indicate that each landing gate is properly closed before the elevator can operate. Each landing gate must have a locking device associated therewith which upon closing mechanically locks the gate in place then electrically indicates that the gate is so closed and on breaking must indicate electrically that it is broken prior to the locking means being mechanically broken.

Presently in use are extension arms connected to the landing gates with a shorting plate of conducting material at the free end which is inserted into an opening in a secured box adjacent the landing gate. The arm is rammed into the hole and mechanically secured therein while the shorting plate makes contact with two normally open contacts and shorts them out providing first the mechanically locking and then the electrical indication that the arm is secured in the box. Often with this device to keep the elevator running and to permit the landing gate to remain open, steel bars are inserted into the opening in the box to short out the normally open contacts therein which is unsatisfactory. Also dirt often accumulates in the opening between the contacts and eventually the contacts are shorted merely by the dirt therein. The shorting plate and the contacts are open to the atmosphere and to the weather elements such that often corrosion sets in, damaging the contacts and necessitating replacement of the whole unit so that it will work electrically.

There are also complicated safety devices on the market which have movable pivot arms that coact with levers to close the normally open contacts which are in a separate box associated therewith. The pivot arm slides in a groove with the lower portion thereof extending into an opening into which enters the extension arm associated with the landing gate. This device has the disadvantage that if the operating parts are out of alignment then the device will not operate as the normally open contacts are not closed. With the landing gates open, foreign material is often jammed into the opening associated with the pivoted arm to close the normally open contacts while the gate remains open. Again as the pivoted arm is opened to the atmosphere and weather elements dirt often enters into the groove and prevents the pivoted arm from moving freely as required to close the normally open contacts.

These disadvantages are overcome by the invention herein disclosed wherein a safety apparatus is provided for use i association with a control circuit and a landing gate for hoist elevators having a probe or arm adapted to fasten the gate mechanically and the arm is also adapted to operate a circuit breaker in a switch box at each gate by means of a magnet secured in the probe or arm and adapted to be positioned adjacent the box in the closed position. Magnetically sensitive contacts which are normally open are positioned within the box and are adapted to be aligned with the magnet in the closed position to close the contacts, the electric hoist control circuit being operatively connected to said magnetically sensitive contact means in said chamber. Preferably, the contacts are arranged on one branch of a parallel circuit having an indicator means and resistor in series with said magnetically sensitive contact means in the other branch of said circuit whereby said normally open contacts in said magnetically sensitive means are closed when said magnetic means are in the closed position providing electrical continuity in the control circuit. The electric circuit is completely enclosed in plastic such as epoxy so that no dust can enter to short the normally open contacts.

The foregoing and other advantages will become apparent from the following description of a preferred embodiment of the invention which is here given by way of example only with reference to the following drawings, in which like references devices refer to like parts thereof through various views and diagrams, in which:

FIG. 1 is a schematic view of the overall electrical circuit for operating the elevator and the safety device according to the invention associated with a number of landing gates;

FIG. 2 is a perspective view of the safety device according to the invention shown partly in section and schematically illustrating the circuit associated therewith, and the box which is used to mechanically secure the extension arm therein;

FIG. 3 is a circuit diagram of the electrical circuit used according to the invention;

FIG. 4 is a circuit diagram showing the electrical circuit according to the invention affected by the permanent magnet in the extension arm;

FIG. 5 is a circuit diagram illustrating the electrical circuit according to the invention when the arm is about to be withdrawn from the first chamber of the box;

FIG. 6 is an alternate embodiment of the invention, and,

FIG. 7 is a further alternate embodiment of the invention.

Referring now to the accompanying drawings, FIG. 1 illustrates schematically a hoist elevator system 10 with a plurality of landing gates 11 associated therewith the hoist itself being omitted. The landing gate 11 moves between an open and a closed position. An extension arm 12 is connected to each landing gate 11 in the upper right-hand comer and is positioned to enter within a switch box 13 as will be described hereinafter provided adjacent each gate 11. Boxes 13 have terminals 14 and 15 extending therefrom for connecting each box 13 electrically in series with one another by an electric line 16 to control circuit output terminals 17 and 18. Control circuit is fed to the output terminals 17 and 18 from a l 10 volt 60 cycle power source 19 through a transformer 20 to the output terminals 17 and 18. Connected in series with the output side of the transformer 20 is a series of windings 21 of a normally open relay control 22 which is connected in an elevator control panel 24 which operates the elevator. The current required to operate the control relay 22 is controlled by any one of gates 11 and boxes 13 and if any one gate 11 is open then the power in the panel 24 is cut off preventing further operation of the elevator.

The switch box 13 is more clearly shown in FIG. 2 and is made of cast aluminum or the like nonpermeable material. The box 13 is rectangular in shape having a body portion 27 and a cover plate 28 attached at the four corners by screws 29. The body portion 27 has two chambers, a first chamber 30 to receive the probe or arm 11 through an opening 31 in an end wall 32 and a second chamber 33 closed from the atmosphere.

In the chamber 33 are contained a magnetic contact system 34 and an electrical circuit 35. The electrical circuit 35 is connected by leads 36 and 37 extending out from the chamber 33 to a terminal box 38 through a channel 39, the box 38 contains the output terminals 14 and 15 therein. The lead 36 extends into the circuit 35 to a junction 36a shown in FIG. 3.

The magnetic system 34 comprises a biassing magnet 40 with an N-pole and an S-pole positioned beneath first and second magnetically sensitive switch contacts 41 and 42 respectively, each connected at one end to terminals 43 and 44 respectively. The free ends 45 and 46 of contact elements 41 and 42 respectively are aligned with one another and overlap so that the free ends 45 and 46 may come in contact as will be described hereinafter. Elements 41 and 42 are arranged in a normally open position. Elements 4] and 42 are hemetically sealed within a glass tube 47.

Preferably contact elements 41 and 42 are spring blade members of suitably treated iron or the like whereby under the influence of a proximate magnetic field they may be drawn together and complete the circuit.

The electrical circuit 35 comprises the input line 36 leading from the terminal 14 to the terminal 44, a line 48 connects a resistor 49 between the terminal 44 and a terminal 50. A neon bulb 51 is connected between terminal 50 and a terminal 52 and a line 53 connects the bulb 51 to a junction 54 and the power output line 37 which is connected to the terminal 15. A line 55 connects the terminal 43 to the junction 54. The magnetic system 34 and the electrical circuit 35 are encapsulated in plastic such as epoxy (not shown) in the chamber 33. Also a sealing material is packed in the channel 39 to the chamber 33 to prevent any water from entering chamber 33.

The chamber 30 into which the arm 12 is inserted comprises a top surface 56 parallel to bottom surfaces 57, 58 and 59 which are in different planes and are joined to the top surface 56 by a sidewall 60. The surface 57 is joined to the surface 58 by an edge 61 and the surface 58 is joined to the surface 59 by an edge 62. The edges 61 and 62 are parallel.

The arm 12 comprises a rectangularly shaped body 63 of bronze or the like with a hooklike portion 64 at one end. At the other end of the body 63 is a hole 65 extending therethrough to be positioned on a pivot pin 66. The pin 66 is secured to a plate 67 that is attached to the landing gate 11 by securing means (not shown). Extending outward from the plate 67 beneath the pin 66 are two stop pins 68 and 69. In the end of the body 63 adjacent the hole 65 is a transverse hole 70 through which passes a link 71 of an operating chain 72. The hooklike portion 64 of the extension arm 12 has a curved outer camming surface 73 joining a vertical surface 74 which engages the vertical surface 62 of the chamber 30 when the arm 12 is inserted in the chamber 30. A slot 76 is cut in the bottom surface 75 of the extension arm 12 and a magnet 77 is bonded therein. The magnet 77 is preferably a permanent magnet and will be aligned as will be described hereinafter. The width of the body 63 of the extension arm 12 should not be greater than the width of the opening 31 to the chamber 30 and the plate 67 is attached to the landing gate 11 in such a manner that the body 63 and hook portion 64 extend into the chamber 30 sufficient distance so that the vertical edge 74 of the hook portion 64 is past the edge 62 of the chamber 30 when the landing gate 11 is closed.

As shown best in FIGS. 4 and the slot 76 is cut in the bottom edge 75 of the extension arm 12 to be aligned with the magnet 40 and the contact elements 41 and 42 of the magnetic system 34.

The biassing magnet 40 is positioned in the chamber 33 beneath the magnetically sensitive elements 41 and 42 and is provided to ensure that the circuit breaks electrically before the arm 12 is removed mechanically from the chamber 30 as described below to cancel out the field of magnet 70 at a predetermined positional relationship, prior to removal of arm 12 from chamber 31.

In operation, an electric current is presented between the terminals 17 and 18 by the power source 19 through the transformer 20. The current travels on the line 16 to the terminal 14 and into the terminal box 13 then out to the terminal and on to the next terminal box 13 and so on until it arrives at the output terminal 17. The electrical current that arrives at the terminal 14 travels along the line 36. There are two paths available for the current to travel from the line 36. Either along the line 48 through the resistor 49 to the terminal 50 through the neon bulb 51 to terminal 52 along line 53 to the junction 54 and by the output line 37 to the terminal 15. Or alternatively, from line 36 to the junction 44 through the magnetically sensitive contact elements 42 and 41 to junction 43 and from junction 43 along line 55 to the junction 54 and along the output line 37 to the terminal 15. The path along the second line through the magnetically sensitive elements 41 and 42 when in contact presents a path of less resistance than the first path through the resistor 49 and neon bulb 51 and therefore, so long as elements 41 and 42 are in contact, all of the current travels through the second path while no current travels along the first path. However, when elements 41 and 42 are separated, a small current flow occurs through the first path, and resistor 49, and lights the neon bulb 51 giving a clear indication whether the gate 11 is closed or open.

When the arm 12 is not in the chamber 30, the magnetically sensitive contact elements 41 and 42 are apart, causing the current to flow along the first path through the resistor 49 and the neon bulb 51 lighting the neon bulb 51 as described and shown in FIG. 3.

So long as gate 11 is open, contact elements 41 and 42 are solely influenced by the field of biassing magnet 40. This field is too weak to cause contacts 41 and 42 to close but does establish a predetermined weak polarity at their ends 45 and 46, one North and the other South.

Upon closing gate 11 the arm 12 enters the chamber 30 of the box 13, the camming surface 73 being positioned in such a manner that it enters the opening 31 without operation of the chain 72 and the remainder of the body portion 63 is also inserted in the chamber 30 until the vertical surface 74 of the hook portion 64 is past the edge 62 in the chamber 30.

When the arm 12 is inserted into the chamber 30 into the position of FIG. 5, the field of magnet 77 influences elements 41 and 42 in the reverse manner to the field of magnet 40, the fields of which are arranged in opposition to one another. However, so long as the arm 12 is in the upper position, the effective field in the region of elements 41 and 42 remains nil and they will not close. This prevents the circuit from being electrically connected before the extension arm 12 is mechanically secured in the chamber 30. When the extension arm 12 drops under gravity into the position shown in FIG. 4

and the vertical edge 74 of the hooklike portion 64 engages the edge 62 of the chamber 30 (see FIG. 4) and closes the gate mechanically.

Magnet 77 is more powerful than magnet 40 with the result that when arm 12 is latched mechanically, magnet 77 overcomes magnet 40 and then influences both elements 41 and 42, the free ends 45 and 46 of which now attract one another and close to complete the circuit. The current from the input line 36 then travels through the elements 41 and 42 shorting out the first path through the resistor 49 and neon bulb 51.

When the operator of the elevator wishes to open the landing gate 11, the chain 72 is pulled in the direction shown by the arrow 78 and the hooklike portion 64 is raised towards the upper surface 56 of the chamber 30. As magnet 77 is raised its influence on contacts 41 and 42 is weakened, but due to residual magnetism the contacts will tend to remain closed too long. The biassing magnet 40, however, overcomes this tendency since as stated its field opposes that of magnet 77. Thus at a certain predetermined positional relationship the field in the region of contacts 41, 42 reverses thereby momentarily releasing contacts 41, 42 from any field whatever and in fact causing momentary repulsion between ends 45, 46 thereof. This effect ensures prompt opening of contacts 41, 42 prior to mechanical releasing of the gate 11. The current from the input line 36 then lights the bulb 51 once more indicating electrically that the arm 12 which was mechanically secured now is broken before the extension arm 12 is removed from the chamber 30.

An alternative embodiment of the invention is illustrated in FIG. 6 wherein a magnet 79 with an N-pole and an S-pole replaces the magnetically sensitive elements 41 and 42. The magnet 79 is pivoted at the S-pole and by a pin 80 and the N- pole end has a contact 81 attached thereto which is spaced apart from a contact 82 connected to the terminal 44a now placed at the end of the input line 36.

The magnet 79 and contacts 81 and 82 are enclosed within a casing 470 which permits the magnet 79 to pivot about the pin 80 and the contacts 81 and 82 to come into engagement when the magnet 77 in the extension arm 12 is moved into the chamber 30. The biassing magnet 40 is positioned as shown with the S-pole positioned next to the N-pole of the magnet 79. The contact 81 is connected to the output terminal 15 by a contact 83 and a line 84 going to the contact 52 then along the line 37 to the terminal 15 to fonn the second branch of the electrical circuit. The first branch of the electrical circuit 35 is exactly as previously described with the resistor 49 and the neon bulb 51 therein.

In operation, when the extension arm 12 is not in the chamber 30, the contact 81 is drawn away from the contact 82 because the N-pole of the magnet 79 is attracted to the S-pole of the bias magnet 40. The current from terminal 14 travels through line 36, terminal 440, resistor 49, neon bulb 51, terminal 52 and line 37 to the terminal 15 lighting up the bulb 51. When the extension arm 12 is positioned directly over the magnet 79 it is attracted to magnet 77, more than to magnet 40. The magnet 79 will pivot on the pin 80 bringing the N-pole towards the S-pole of the magnet 77 closing contacts 81 and 82 and the current will flow from terminal 14 along line 36 through terminal 44a, contact 82, contact 81, terminal 83, line 84, terminal 52 and line 37 to terminal 15.

When the arm 12 is lifted to a position corresponding to that in FIG. 5, the S-pole of the magnet 77 has been moved away from the N-pole of the magnet 79 in such a manner that the force created by the S-pole of the magnet 40 is greater than that created by the S-pole of the magnet 77 and the N-pole of the magnet 79 is attracted towards the S-pole of the bias magnet 40 and the contacts 81 and 82 are broken. The current then flows through the resistor 49 and neon bulb 51 and the neon bulb 51 lights up indicating that the connection has been broken electrically before the mechanical lock of the arm 12 in the chamber 30 is broken as required by law.

A further alternative embodiment is shown in FIG. 7. The embodiment as shown in this case is essentially the same as that shown in FIGS. 1 to 5 with the exception that the entire unit is reoriented 90. In this way, the mechanical fastening member can be arranged to operate along the vertical up and down axis entering a mechanical locking opening which is arranged in a horizontal plane. This particular embodiment is found to be more suitable in certain circumstances, for example, where it may be desirous to locate the safety switch and locking mechanism at intermediate points along the gate rather than along one edge, and is also found to be able to withstand certain kinds of operator abuse more successfully.

Obviously, the portion of housing 27 defining chamber 30 and the latching portions thereof can be constructed separately from chamber 33 without altering the invention in any way.

As shown in FIG. 7, the switch casing or housing 27 has a cover plate 29, and is provided in its interior with contact elements 41, 42 having overlapping ends 45, 46 as in the case of FIG. I. A biassing magnet referenced as 40a is located adjacent one end of one of contacts 41, 42, although the precise location can vary as shown in phantom to any location where it operates in the most effective manner. An indicator light referenced as 51 is provided on one sidewall of the housing 57 and a cable is connected at any suitable waterproof junction 90, light 51 and junction 90 being preferably provided on a sidewall of casing 27 whereby to avoid harmful accumulations of moisture and dirt. Housing 27 is preferably fastened by any suitable means (not shown) to a mounting plate 91 fastened by screws 92 to a suitable adjacent part of the framework of the hoist tower indicated 10 in FIG. 1. An angled ramp 93 is provided extending along the lower edge of mounting plate 91 and having a latching opening 94 extending therethrough in registration with contact element 41, and a soft iron magnetic shunt member is welded or otherwise suitably fastened to ramp 93 in registration with contact element 42 for purposes to be described. In order to eiTect mechanical latching of a gate 11, a latching bolt member 96 preferably consisting of a bar of stainless steel or the like of a suitable diameter to pass easily through latching opening 94, is slidably mounted in the bracket member 97 having upper and lower bearing plates 98 each provided with openings 99 therethrough, through which bolt 96 is adapted to be slidably mounted. Bolt 96 is provided with a compression spring 100 encircling the same between bearing plate 99, and a pin member 101 extends therethrough to compress spring 100 when bolt 96 is drawn downwardly. Any suitable operating chain 102 is provided, fastened to the lower end of bolt 96. As noted, mounting bracket 97 can be mounted to a hoist gate indicated generally as 11 at any intermediate point across its width, in this case being shown.

mounted more or less midway between the two sides of gate 1 1 on a central strut indicated as S whereby to facilitate access to the chain 102 by an operator. In the upper end of bolt 96, there is provided a magnet 103 embedded in a recess therein as shown in FIG. 7.

As in the case of the embodiment of FIG. 2, magnet 103 is substantially stronger than magnet 40a and is so arranged that the field established by magnet 103 is in opposition to the field established by magnet 40a. Thus, when the gate is opened, and the latch or bolt 46 is removed from opening 94, the contact elements 41 and 42 will remain open, although subject to the field of magnet 40a, since magnet 40a is too weak to draw the ends 45 and 46 together. Once the gate is closed, the bolt 96 enters the opening 94, and the field of magnet 103 overcomes the relatively weak field of magnet 40a being assisted in the connection by the magnetic shunt member 95, and the iron present in ramp 93. Thus the magnetic lines of flux emanating from magnet 103 are carriedthrough ramp 93 and shunt thereby intensifying the field in the region of contacts 41 and 42 and ensuring that the ends 45 and 46 snap closed in a positive manner. Upon bolt 96 being drawn downwardly, the effect of the biassing magnet 40a is the same as is described in connection with the embodiment of FIG. 2. In addition, however, magnet 40a is assisted by the fact that as magnet 103 passes downwardly through the opening 94 in ramp 93, the ramp 93 continues to act as a magnetic shunt, although now in this position it is acting as a shunt with respect to the field emanating from the upper end of the magnet 103, thereby causing a reversal of the field as it passes through such openmg.

It will be noted therefore, that in this embodiment of the invention, the mechanical latching is effected entirely by the bolt 96 and the ramp 93, independently of any contact with the switch housing, and it becomes unnecessary to provide any chamber within the switch housing 27 for reception of a locking bar or the like as was the case in FIG. 2.

The function of the light 51 and the related circuitry is essentially the same as that in the case of FIG. 2.

The foregoing is a description of preferred embodiments of the invention only. The invention is not to be taken as limited to any of the specific features described, but comprehends all such variations as come within the spirit and scope of the claims.

What I claim is:

I. Hoist control apparatus for use in association with an electrically operated hoist having a plurality of landing gates of the type having control switch means associated with each said landing gate operable to prevent operation of said hoist when any one or more of said gates is left open, said control apparatus comprising:

a scalable container mountable on said hoist adjacent each said landing gate;

magnetically sensitive contact means mounted within said container, and responsive to a proximate magnetic field of predetermined strength to close with one another, removal of said proximate field causing said contacts to open apart;

connection means associated with each of said contact means adapted for connection in a control circuit for said hoist;

a movable latching member adapted to be mounted on a said landing gate, and movable towards and away from said scalable container;

magnetic means in said latching member adapted to operate said contact means when said latching member is moved towards said container, and,

lamp means electrically connected with said contact means by means of indicator circuit means operable to activate said lamp means when said contacts are open and being rendered inactive when the same are closed.

2. Apparatus as claimed in claim I, wherein said container is made of nonpermeable material and including latch receiving means associated with said container made of ferrous material, at least a portion thereof being adapted and oriented to operate as a magnetic shunt with respect to the field of said magnet means in said latching member, said lamp means being mounted so as to be visible from the exterior of said container.

3. Apparatus as claimed in claim 1, including bias magnet means mounted in said container spaced from said contact means whereby to establish a magnetic field around said contact means of predetermined strength, said bias magnet field being arranged in opposition to the field of said latching magnet.

4. Apparatus as claimed in claim 1, including means for releasably receiving said latching member, said receiving means being adapted to be fastened to a portion of said hoist adjacent to a said gate, said receiving means defining an opening dimensioned and oriented to receiving said latching member as the same is moved towards said sealable container,

and providing a mechanical fastening for said gate, said gate.

being movable only upon release of said latching member.

5. Apparatus as claimed in claim 1, wherein said landing gates are movable along predetermined horizontal paths, and wherein said latching members are adapted to be mounted on respective said gates for latching and unlatching movement relative to said gates along a predetennined linear path normal to the path of movement of said gates, and latch receiving members mounted on said hoist adjacent respective said gates for mechanically engaging said latching means when the same is moved towards said sealable container and mechanically latching said landing gate.

6. Apparatus as claimed in claim 1, wherein said latching member is of generally hook-shaped construction, means swingably mounting said latching member on its respective said landing gate, and catch means on said scalable container, oriented and arranged to make interlocking engagement with said hook-shaped portion, for mechanically latching said landing gate.

7. Apparatus as claimed in claim 1, wherein each said latching member comprises a metal bar, a recess formed in said bar, and a permanent magnet embedded and secured in said recess.

8. Apparatus as claimed in claim 1 wherein said indicator circuit means comprises a bridging circuit across said contact means, and resistance means biassing current to flow normally through said contact means when the same are closed, said resistance means being adapted to permit current flow therethrough, and through said lamp means when said contacts are open.

9. Hoist control apparatus for use in association with an electrically operated hoist having a plurality of landing gates of the type having control switch means associated with each said landing gate operable to prevent operation of said hoist when any one or more of said gates is left open, said gates being movable between open and closed positions, along a predetermined linear path, relative to a door frame assembly on said hoist, said control apparatus comprising;

a sealable container means mountable on each said door frame of said hoist adjacent each said landing gate, offset to one side of said predetermined linear path of movement of its respective said gate;

magnetically sensitive contact means mounted within said container, and responsive to a proximate magnetic field of predetermined strength to close with one another, removal of said proximate field causing said contacts to open apart;

connection means associated with each said contact means adapted for connection in a control circuit for said hoist;

a movable latching member adapted to be mounted on one side of a said landing gate, so as to pass into and out of registration with said sealable container, closely adjacent thereto, when moving along its predetermined path of movement, said movable latching member being axially movable along a predetermined path normal to the path of movement of said landing gate towards and away from said sealable container;

spring means normally urging said latching member towards said scalable container, and manually operable means for withdrawing the same therefrom;

magnetic means in one end of said latching member, proximate to said sealable container, when the same are located in registration with one another, and adapted to operate said contact means therein when in registration as aforesaid;

ramp mean mountable on said door frame of said hoist adjacent said sealable container, and adapted to interengage with said proximate end of said latching member while said landing gate is moving into registration with said sealable container, whereby to depress said latching member against said spring means, and locking opening means in said ramp means dimensioned to snugly receive said latching member therein, said opening means being in registration with said sealable container; and,

the strength of the magnetic field of said magnetic means in said latching member being such that when said latching member is received within said opening in said ramp means, said contact means are closed thereby, and when said latching member is withdrawn against said spring biassing means, from said locking opening, said contact means are released from said field, and open apart thereby ensuring positive operation of said contact means, prior to physical unlocking of said latching means.

10. The apparatus as claimed in claim 9 wherein said ramp means is curved at one end, and is formed of permeable material, and including magnetic shunt means connected with said ramp means, whereby to provide a sharp cutoff of the effect of said magnetic field of said latching member upon withdrawal thereof from said locking opening, said shunt means cooperating with the magnetic field of said latching member, when the same is in interlocking engagement with said locking opening, so as to maintain said contact means closed.

ll. The apparatus as claimed in claim 9 including lamp means, said lamp means being mounted so as to be visible from the exterior of said container.

12. Hoist control apparatus for use in association with an electrically operated hoist having a plurality of landing gates of the type having control switch means associated with each said landing gate operable to prevent operation of said hoist when any one or more of said gates is left open, and having door frame means defining respective landing gate openings of said hoist, each said landing gate being operable between closed and open positions along a predetermined linear path, said control apparatus comprising;

a scalable container mountable on said door frame of said hoist adjacent each said landing gate, aligned with said predetermined path of movement of said landing gate, whereby said landing gate moves directly towards and away from said sealable container upon closing and opening movement as aforesaid;

Magnetically sensitive contact means mounted within said container, and responsive to a proximate magnetic field of predetermined strength to close with one another, removal of said proximate field causing said contact means to open apart;

connection means associated with each of said contact means adapted for connection in a control circuit for said hoist;

latching recess means formed in said sealable container, adapted to be aligned with said predetermined path of movement of said landing gate, and defining an open mouth directed along said predetermined path;

locking step means within said latching opening, at a predetermined distance from said open mouth thereof,

a latching member adapted to be pivotally mounted on said landing gate, and having a free end extending from said landing gate and oriented and adapted to enter said latching opening in said sealable container upon closing of said landing gate;

member from said recess, said contact means are released from said magnetic field, whereby to ensure positive operation of said contact means prior to mechanical release of said gate by said latching member,

and, lamp means electrically connected with said contact means by means of indicator circuit means operable to activate said lamp means when said contacts are open and being rendered inactive when the same are closed. 

1. Hoist control apparatus for use in association with an electrically operated hoist having a plurality of landing gates of the type having control switch means associated with each said landing gate operable to prevent operation of said hoist when any one or more of said gates is left open, said control apparatus comprising: a sealable container mountable on said hoist adjacent each said landing gate; magnetically sensitive contact means mounted within said container, and responsive to a proximate magnetic field of predetermined strength to close with one another, removal of said proximate field causing said contacts to open apart; connection means associated with each of said contact means adapted for connection in a control circuit for said hoist; a movable latching member adapted to be mounted on a said landing gate, and movable towards and away from said sealable container; magnetic means in said latching member adapted to operate said contact means when said latching member is moved towards said container, and, lamp means electrically connected with said contact means by means of indicator circuit means operable to activate said lamp means when said contacts are open and being rendered inactive when the same are closed.
 2. Apparatus as claimed in claim 1, wherein said container is made of nonpermeable material and including latch receiving means associated with said container made of ferrous material, at least a portion thereof being adapted and oriented to operate as a magnetic shunt with respect to the field of said magnet means in said latching member, said lamp means being mounted so as to be visible from the exterior of said container.
 3. Apparatus as claimed in claim 1, including bias magnet means mounted in said container spaced from said contact means whereby to establish a magnetic field around said contact means of predetermined strength, said bias magnet field being arranged in opposition to the field of said latching magnet.
 4. Apparatus as claimed in claim 1, including means for releasably receiving said latching member, said receiving means being adapted to be fastened to a portion of said hoist adjacent to a said gate, said receiving means defining an opening dimensioned and oriented to receiving said latching member as the same is moved towards said sealable container, and providing a mechanical fastening for said gate, said gate being movable only upon release of said latching member.
 5. Apparatus as claimed in claim 1, wherein said landing gates are movable along predetermined horizontal paths, and wherein said latching members are adapted to be mounted on respective said gates for latching and unlatching movement relative to said gates along a predetermined linear path normal to the path of movement of said gates, and latch receiving members mounted on said hoist adjacent respective said gates for mechanically engaging said latching means when the same is moved towards said sealable container and mechanically latching said landing gate.
 6. Apparatus as claimed in claim 1, whereIn said latching member is of generally hook-shaped construction, means swingably mounting said latching member on its respective said landing gate, and catch means on said sealable container, oriented and arranged to make interlocking engagement with said hook-shaped portion, for mechanically latching said landing gate.
 7. Apparatus as claimed in claim 1, wherein each said latching member comprises a metal bar, a recess formed in said bar, and a permanent magnet embedded and secured in said recess.
 8. Apparatus as claimed in claim 1 wherein said indicator circuit means comprises a bridging circuit across said contact means, and resistance means biassing current to flow normally through said contact means when the same are closed, said resistance means being adapted to permit current flow therethrough, and through said lamp means when said contacts are open.
 9. Hoist control apparatus for use in association with an electrically operated hoist having a plurality of landing gates of the type having control switch means associated with each said landing gate operable to prevent operation of said hoist when any one or more of said gates is left open, said gates being movable between open and closed positions, along a predetermined linear path, relative to a door frame assembly on said hoist, said control apparatus comprising; a sealable container means mountable on each said door frame of said hoist adjacent each said landing gate, offset to one side of said predetermined linear path of movement of its respective said gate; magnetically sensitive contact means mounted within said container, and responsive to a proximate magnetic field of predetermined strength to close with one another, removal of said proximate field causing said contacts to open apart; connection means associated with each said contact means adapted for connection in a control circuit for said hoist; a movable latching member adapted to be mounted on one side of a said landing gate, so as to pass into and out of registration with said sealable container, closely adjacent thereto, when moving along its predetermined path of movement, said movable latching member being axially movable along a predetermined path normal to the path of movement of said landing gate towards and away from said sealable container; spring means normally urging said latching member towards said sealable container, and manually operable means for withdrawing the same therefrom; magnetic means in one end of said latching member, proximate to said sealable container, when the same are located in registration with one another, and adapted to operate said contact means therein when in registration as aforesaid; ramp mean mountable on said door frame of said hoist adjacent said sealable container, and adapted to interengage with said proximate end of said latching member while said landing gate is moving into registration with said sealable container, whereby to depress said latching member against said spring means, and locking opening means in said ramp means dimensioned to snugly receive said latching member therein, said opening means being in registration with said sealable container; and, the strength of the magnetic field of said magnetic means in said latching member being such that when said latching member is received within said opening in said ramp means, said contact means are closed thereby, and when said latching member is withdrawn against said spring biassing means, from said locking opening, said contact means are released from said field, and open apart thereby ensuring positive operation of said contact means, prior to physical unlocking of said latching means.
 10. The apparatus as claimed in claim 9 wherein said ramp means is curved at one end, and is formed of permeable material, and including magnetic shunt means connected with said ramp means, whereby to provide a sharp cutoff of the effect of said magnetic field of said latching member upon withdrawal thereof from saId locking opening, said shunt means cooperating with the magnetic field of said latching member, when the same is in interlocking engagement with said locking opening, so as to maintain said contact means closed.
 11. The apparatus as claimed in claim 9 including lamp means, said lamp means being mounted so as to be visible from the exterior of said container.
 12. Hoist control apparatus for use in association with an electrically operated hoist having a plurality of landing gates of the type having control switch means associated with each said landing gate operable to prevent operation of said hoist when any one or more of said gates is left open, and having door frame means defining respective landing gate openings of said hoist, each said landing gate being operable between closed and open positions along a predetermined linear path, said control apparatus comprising; a sealable container mountable on said door frame of said hoist adjacent each said landing gate, aligned with said predetermined path of movement of said landing gate, whereby said landing gate moves directly towards and away from said sealable container upon closing and opening movement as aforesaid; Magnetically sensitive contact means mounted within said container, and responsive to a proximate magnetic field of predetermined strength to close with one another, removal of said proximate field causing said contact means to open apart; connection means associated with each of said contact means adapted for connection in a control circuit for said hoist; latching recess means formed in said sealable container, adapted to be aligned with said predetermined path of movement of said landing gate, and defining an open mouth directed along said predetermined path; locking step means within said latching opening, at a predetermined distance from said open mouth thereof, a latching member adapted to be pivotally mounted on said landing gate, and having a free end extending from said landing gate and oriented and adapted to enter said latching opening in said sealable container upon closing of said landing gate; hook means on said free end of said latching member adapted to interengage with said locking step means, whereby to effect locking of said landing gate by mechanical means; magnetic means in said free end of said latching member adapted to operate said contact means when said latching member is moved fully into said latching recess of said container with said hook means in engagement with said locking step therein, said magnetic means providing magnetic field such that upon partial removal of said hook member from said recess, said contact means are released from said magnetic field, whereby to ensure positive operation of said contact means prior to mechanical release of said gate by said latching member, and, lamp means electrically connected with said contact means by means of indicator circuit means operable to activate said lamp means when said contacts are open and being rendered inactive when the same are closed. 